In the field of digital storage devices wherein data may be retrieved relatively rapidly, Winchester or hard disk drives are widely used. These units characteristically include a substantial number of hard disks, in a stack, with disks having magnetizable surfaces. These disks are rotated at high speeds, and magnetic heads are moved in a generally radial configuration, with the magnetic heads in close proximity to the disks, to read and write information on the disks. In view of the demands for rapid access time to the data, the head positioners move relatively rapidly to shift the heads from the innermost track to the outermost track and vice versa. With this rapid angular movement of the head positioner, it is useful to have stop arrangements provided which will positively stop the angular rotation of the head positioner, and absorb the energy of rotation, and accomplish this without undue shock in the unexpected event of failure of the servo electronics. So that the drive and the data recorded on the disks can be salvaged by replacing only the electronics, for example, the presence of shock absorbing stop arrangements may prevent damage to the head positioner assembly and to the head mounting arrangements. In addition, the space within a Winchester or hard disk drive is severely limited, so the stop arrangements must occupy minimal volume within the unit.
Accordingly, a principal object of the present invention is to provide compact arrangements for stopping the angular motion of the head positioner of a hard disk drive, without undue shock being applied to the rotatable head positioner, and accomplishing this object in minimal space.